"Flappy Bird has unexpected effects," says Nguyen. "It causes addiction (in) people. I think it is an unexpected problem ... and I have to remove it."

The mobile game features a bird players must navigate through a series of pipes extending from the top and bottom of the screen. Players tap the screen to keep the bird airborne. Flappy Bird was known for being highly challenging, as the slightest graze against a pipe ended the game.

The game, first released on Apple's App Store in May, surged to popularity in recent months, culminating with the game's surge to the top of iTunes and Google Play download charts. Nguyen estimates Flappy Bird has been downloaded 50 million times.

Nguyen cites people "sharing their scores on social networks" as a key reason for Flappy Bird's ascent, and denies claims that he used questionable tactics to inflate the game's rankings.

"I respect other people's opinions about my games," says Nguyen. "I am sure I didn't cheat anything, and I don't have to do that."

Nguyen puzzled many fans of his game by revealing on Twitter Saturday that he planned to pull it down. "I cannot take this anymore," Nguyen wrote on February 8.

The Vietnam-based game designer has other games available for mobile devices, including Shuriken Block and Super Ball Juggling. Nguyen says he will continue to make mobile games. But, would Nguyen ever consider bringing back Flappy Bird? "I keep my words."